449 research outputs found
Аналіз композиційно-конструктивного устрою одягу для провідників залізничного транспорту України
The article described the current uniforms for railway workers of Ukraine. On the basis of theoretical studies are organized by compositional and structural features varieties of sets of uniforms for men and women for the conductor rail. Found insufficient quality ergonomic, aesthetic and reliability, formulated the task of developing assortment series sets with improved quality.В статье охарактеризована существующая форменная одежда для работников железнодорожного транспорта Украины. На основе теоретических исследований систематизированы согласно композиционно-конструктивным признакам разновидности комплектов форменной мужской и женской одежды для проводников железнодорожного транспорта. Выявлен недостаточный уровень качества эргономических, эстетических и показателей надежности, сформулированы задачи по разработке ассортиментных рядов комплектов с улучшенными показателями качества.В статті надано характеристику існуючого форменого одягу для працівників залізничного транспорту України. На основі теоретичних досліджень систематизовано за композиційно-конструктивними ознаками різновиди комплектів форменого чоловічого та жіночого одягу для провідників залізничного транспорту. Виявлено недостатній рівень якості ергономічних, естетичних та показників надійності, сформульовано завдання щодо розробки асортиментних рядів комплектів з покращеними показниками якості
Substantiation of parameters of mine working drivage with blasting technique and cleaning charges in advance cutting holes
Drilling and blasting operations (D&B) are the most difficult and laborious operations in the process of
mineral extraction, requiring permanent development and upgrading of methods and equipment. The aim of the study is to substantiate the parameters of drilling and blasting drivage of horizontal and inclined (up to 12o) mine workings on the basis of high-performance self-propelled equipment and new designs of box cuts with cleaning explosive charges (0.2 kg of 6ZhV ammonite), placed in advance holes of 65 to 105 mm in diameter. The paper presents the results of the analysis of practical experience and scientific achievements in the field of drilling-andblasting rupture of solid media and continuum mechanics. The need for new designs of box cuts, reliability of which in the formation of high-quality (clean) cut cavity reaches 0.95-1.00, was substantiated. New design options of box cuts have been developed, the peculiarity of which consists in provision of sufficient compensation (peripheral) volume with the use of blast hole cut charges for blasting rupture of trapezoidal partitions, with the compensation volume factor of 2.50 to 1.34. Promising areas of research were shown using the example of complicated
structure ore deposits and large faults in the Kirovograd ore district and crystalline rocks of the Ukrainian shield at the following mines of Ukraine: PJSC KZhRK, CJSC Sukhaya Balka (Kryvyi Rih), Vostok-Ruda LLC, SE VostGOK (Zheltye Vody), CJSC ZZhRK, etc. Promising areas of research were proposed using the example of complicated structure ore deposits typically formed at the junction of large faults; besides, the use of environmentally friendly emulsion explosives and self-propelled emulsion explosive chargers was recommended
Розчинність карбону, мангану та силіцію в γ-залізі сплавів системи Fe-Mn-Si-C
The study was performed on alloys with a carbon content of 0,37-0,57 % (wt.), silicon 0,23-0,29 % (wt.), manganese 0,7-0,86 % (wt.), the rest– iron. To determine the phase composition of alloys used microstructural, microanalysis and X-ray analysis. In addition, the physical characteristics of the alloys studied in this paper were determined, such as alloy chemical dependence of extension and contraction ratio, impact toughness and hardness. The results obtained in this paper showed that the iron-based alloy with the content of carbon of 0.57 % (wt.), silicon of 0.28 % (wt.) and manganese of 0.86 % (wt.)) had the superior microstructure and physical properties. It was determined that after a number of crystallization and phase transformation the alloy phase structure includes two phases: a-iron and cement magnesium doping Fe2.7Mn0,3C..
For the first time using the method quasichemistry received an expression of the free energy of a γ-iron alloyed with silicon and magnesium, and determined the solubility limit of carbon, manganese and silicon. The maximum content in γ-iron can reach: carbon 6,8 % (at.), manganese – 67,5 % (at.), silicon – 2,3 % (at.).Дослідження проводили на сплавах з вмістом карбону 0,37-0,57 % (мас.), силіцію 0,23-0,29 % (мас.), мангану 0,7-0,86 % (мас.), решта – залізо. Для визначення фазового складу сплавів використовували мікроструктурний, мікрорентгеноспектральний та рентгеноструктурний аналізи. В роботі були визначені фізичні характеристики сплавів, що досліджували в даній роботі, а саме, залежність відносного видовження, відносного звуження, ударної в’язкості та твердості від хімічного складу сплаву. Отримані в даній роботі результати показали, що найкращі мікроструктурні та фізичні характеристики має сплав на основі заліза з вмістом карбону 0,57 % (мас.), силіцію 0,28 % (мас.), мангану 0,88 % (мас.). Визначено, що після кристалізації та низки фазових перетворень фазовий склад сплаву представлений двома фазами: a-залізом та легованим манганом цементитом Fe2.7Mn0,3C.
Вперше за допомогою методу квазіхімічного методу отримали рівняння вільної енергії твердого розчину γ-заліза, легованого силіцієм і манганом, і визначили межу розчинності карбону, мангану і силіцію. Максимальний вміст карбону в γ-залізі може досягати 6,8 % (ат.), мангану 67,5 % (ат.) та силіцію 2,3 % (ат.)
Hyperglycemia and possible mechanisms of β-cell damage in patients with COVID-19
Progressive decrease in the weight and functional reserve of β-cells is one of the main pathogenetic mechanisms of development of type 2 diabetes mellitus (DM2). The rate of progression of these processes is strictly individual, which largely determines the course of DM2 and the effectiveness of the therapy. As a rule, apoptosis and necrosis are the main mechanisms of β-cell damage and death in CD2. At the same time, recent studies allow us to consider the destruction and death of β-cells as the outcome of other types of programmed cell death (PCG), the role of innate immunity in the Genesis of CD2 IS actively discussed. This article provides an overview of the data of domestic and foreign literature of recent years regarding the molecular, intracellular characteristics of different types of β-cell PCG in CD2. The results of studies aimed at studying the possible factors and processes leading to their launch are presented
Photoluminescence of the GaAs Superlattices with Quasi-Delta-Doped Layers
The GaAs short-period superlattices have been grown for the first time by the metal-organic hydride epitaxy
method using Se and C for quasi-\delta-doping. Photoluminescence spectra measured at 4.2 K display well-distinguished
peaks, which coincide with transitions between quantizied levels of electrons and holes in the potential relief quantum
wells. To describe observed phenomena in quasi-\delta-doped superlattices a theory is developed with taking into account
existing tails of the density of states
Ethnic differences in risk factors and prevalence of type 2 diabetes in the adult population of the Russian Federation
BACKGROUND: Russia is one of the most multinational states in the world. Identification of ethnic groups with a higher risk of developing DM2, analysis of risk factors for the development of DM2 will allow developing personalized approaches to the prevention and treatment of DM2.AIMS: To reveal ethnic features of the prevalence of carbohydrate metabolism disorders and risk factors for the development of DM2 in the adult population of the Russian Federation.MATERIALS AND METHODS. A retrospective analysis of the database of the national epidemiological cross-sectional study NATION was carried out. Depending on the self-specified nationality, on the basis of anthropological characteristics, the following ethnic groups were identified: “Mongoloid population”, “Peoples of the Volga region”, “Peoples of the North Caucasus”, “Peoples of Transcaucasia”, “Russians”. The analysis consisted of several stages and included: analysis of the anthropometric features of the selected groups, taking into account the presence of carbohydrate metabolism disorders (MO); study of the prevalence of violations of the MA in the selected ethnic groups; analysis of ethnic characteristics of risk factors for the development of type 2 diabetes; analysis of the frequency of violations of the MA in various ethnic groups, taking into account the territory of residence. MR disorders were defined as the presence of DM and/or prediabetes. In accordance with the WHO criteria, HbA1c≥6.5% corresponded to the diagnosis of DM, HbA1c values in the range of 5.7%≤HbA1c<6.5% to the diagnosis of prediabetes.RESULTS: The highest frequency of violations of the MA was observed in the group «Peoples of the Volga region» (31.2%), the lowest in the «Peoples of the North Caucasus» (15.6%). BMI in the group “Peoples of the Volga region” was significantly lower than in the group “Peoples of the North Caucasus. Violations of MR were more often observed in the abdominal nature of obesity, obesity of the 1st stage, age over 45 years in the groups «Mongoloid population» and «Peoples of the Volga region» than in the peoples of the «Northern Caucasus» and «Transcaucasia». The frequency of occurrence of SR violations among representatives of the Volga Peoples group living in their historical territories was higher than among Russians living in the same regions: 32.5% and 24.3% (p<0.001 χ2 criterion), and also higher than in the Russian CFD: 32.5% and 27.4%, respectively, p=0.001 (χ2 test). The prevalence of violations of the MA among the peoples of the North Caucasus was less than among the Russians of the Central Federal District — 13.9% and 27.36%, respectively (p<0.001 χ2 criterion). The prevalence of MR violations among representatives of the “Peoples of the North Caucasus” group living in their historical territories (n=598) was less than among those living in other regions of the Russian Federation (n=164) (13.9% and 21.95%, p= 0.012 criterion χ2).CONCLUSION: In the present work, for the first time, we analyzed the prevalence of MR disorders in various ethnic groups of the population of the Russian Federation, identified certain ethnic characteristics of DM2 risk factors and their contribution to the development of the disease. The obtained results should be used for planning preventive programs in various regions of the Russian Federation
High level of glycated hemoglobin (HbA<sub>1c</sub>) in patients with COVID-19 is a marker of the severity of the infection but not an indicator of previous diabetes mellitus
BACKGROUND: Less than a year has passed since the start of the new coronavirus infection COVID-19 pandemic caused by SARS-CoV-2. First published research results demonstrate a frequent increase in glycemia in patients without previously diagnosed carbohydrate metabolism disorders. A possible relationship between the carbohydrate metabolism state and the course of COVID-19 is considered.AIM: To identify the incidence of known and newly diagnosed diabetes mellitus (DM) in hospitalized patients with COVID-19 and evaluate the relationship between glycated hemoglobin (HbA1c), inflammation markers and infectious disease severity.METHODS: A single-center, cross-sectional, retrospective study included 155 patients with confirmed COVID-19 and bi- lateral polysegmental viral pneumonia hospitalized in the Endocrinology Research Centre, Russian Federation. Diagnosis of carbohydrate metabolism disorders was based on the HbA1c level, blood glucose level at admission (BGA) and fasting plasma glucose (FPG). Patients were divided into 2 groups: without the previously diagnosed DM (n=129, 83.3%) and with known history of DM (n=26, 16,7%). Patients without previously diagnosed DM were divided into subgroups according to HbA1c levels: ≤6,0% (Group A), >6,0% HbA1c, <6.5% (Group B), ≥6,5% (Group C). Additionally, insulin, interleukin 6 (IL-6) and D-dimer levels were measured in all patients. Blood oxygen saturation (SpO2) was measured by pulsoximetry, computerized tomography of lungs with calculation of lung parenchyma damage percentage.RESULTS: Type 2 DM was previously established in 16.7% of all included patients. Among patients without DM history, DM was revealed in 8 patients (5.2%), based on HbA1c, FPG and BGA. In 66 patients (42.6%) we observed no changes in carbohydrate metabolism. In 55 patients, the interpretation of carbohydrate metabolism state was difficult due to inconsistency of HbA1c level with FPG and BGA: in particular, the level of HbA1c ≥ 6.5% (which corresponds to the diagnostic threshold of the DM) was detected in 19 patients (12,2%) with normal FPG and BGA. No true stress hyperglycemia on admission and according to FPG was reported. Despite the presence of confirmed DM, HbA1c levels positively correlated with inflammatory markers (erythro- cyte sedimentation rate, C-reactive protein, IL-6) and SpO2. Patients with a HbA1c ≥6.5% without DM history had the most severe course of the disease: longest duration of hospitalization, largest damage of the pulmonary tissue, and high lethality.CONCLUSION: The incidence of DM among patients hospitalized with COVID-19 was 21.9% (16.7% had previous diagnosis of DM, 5.2% — newly diagnosed), which is 1.5 times higher than in general population in a comparable age category. It is difficult to assess the carbohydrate metabolism disorders in patients in acute infectious period. An increased level of HbA1c (≥6.5%), first detected in the acute period of infection, in combination with normal FPG and BGA parameters, cannot be a diagnostic criterion and requires dynamic monitoring. HbA1c level can be considered as a predictive factor of COVID-19 severity, independent of DM
Research of topography of influence and classification of the requirements for uniform of passenger car attendants
The article investigates the theoretical foundations of the study of reliability indicators in order to identify priorities in development of efficient uniform for the passenger car attendants with predictable properties. Thus, functional and constructive design is carried out, taking into account the topography of influence by defining zones of influence on different parts of the garment, what enables development of variable constructive and functional solutions for the uniform in accordance with the quality requirements
Using an Indoor Localization System for Activity Recognition
Recognizing the activity performed by users is importantin many application domains, from e-health to home automation. Thispaper explores the use of a fine-grained indoor localization system, basedon ultra-wideband, for activity recognition. The user is supposed to weara number of active tags. The position of active tags is first determinedwith respect to the space where the user is moving, then some position-independent metrics are estimated and given as input to a previouslytrained system. Experimental results show that accuracy values as highas∼95% can be obtained when using a personalized model
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